Internal combustion engine



March 11, 1941. c. N. M|Tc|-|ELL INTERNAL COMBUSTION ENGINE Original Filed April 30, 1928 I NV EN TOR.

Patented Mar. 11,1941

UNITED STATES PATENT yori-ICE t nvrmuim.l asoma u I l courtney minuten. summits. om@ origina appresa smi n, ma, serai s.

Divided and this application `,lune 25, y1938. Serial No. 215,753

somma. (cl. ietf-sz) This invention relates to an internal combustion engine and thisP application is a divisionl oi' my application Serial No. 274,133, .filed April 30, 1928, and renewed December 2, i932. Its particular features are those shown in Figs. 4 and 5 ofthe l0 pulverize the fuel and mix it` with the air at the y time of injection. Due to air under the high pressures existing in the, cylinder at the time of injection being very resistant to penetration by fuel as deliveredlby an injector, means must. be provided to effect this penetration by.. causing the air to pass the nozzle of the injector in a stream oi limited thickness. Failure to obtain penetration results in incomplete combustion v causing smoky exhaust and loss of fuel due to over-rich mixtures: or, if-all the fuel is to be burned completely, an excess of air must be present to effect this which results in low mean elfective pressures and low power out-pnt. These conditions are emphasized by the results obtained when attempts are made to operate an engine of this kind at high speeds.

The principal object of this invention is to provide means for obtaining penetration of the air by the fuel stream. 'A further object is to' I provide an arrangement whereby this penetration is independent of the operating speed of the engine. Another object. is to provide an engine which will deliver a highl power out-put for each unit of plston'displacementvolume. Another object is to provide an engine which will be free from smoke, odors and other ola-'- noxious conditions resulting from incomplete combustion. A still further object is to provide an internal combustion engine which can be 40 manufactured at a relatively low cost and 'from a limited weight of material, and one which will require a' minimum amount of repair and service In attaining these objects, this invention contemplates a combustion chamber construction inwhichamaterialportlon oftheairof compression itself is directed past the injector noa- `zle in a thin, peuetrable stream in order to secure the desired uniform and finely divided mixture of fuel and air within the working cylinder and with the most simple arrangement oi' parts.

Fig. 1 is a section through the engine showing the general arrangement of parts related to the improved combustion chamber.

Fig. 2 is an enlarged fragmentary section of thev combustion chamber and related parts. Fig. 3 is a section on line I--I of a portion of the pis- -ton as indicated in Fig. 2. Fig. 4 is a fragmentary section on line 2--2 of Fig. 2 and for purpose of greater clearness has been addedl to the draw- 5 ing.

As this invention is concerned'primarily with the elements of the combustion chamber, only a brief mention will be made of the other elements entering into the engine mustrated in the draw- 1ol ing.v The crank case Iis cl'o at its lower side with the engine pan, 2 and is provided at its upper side with cylinder block 3 upon which is arranged cylinder head l. The crank shaft 5 v is mounted inbearings .carried by-crank case I l5 and is joinedmby connecting rod S to piston I which is of special construction. The cam shaft 3 is driven from the crank shaft 5 by means o the usual train of seais or by chain and sprockets. The push rods 31 and I0 are actuated by 20 cam shaft 3 through the medium of tappets I3. The push rod t, which is concealed by push rod y I3, actuates rocker arm. Il and pushv rod I0 actuates rocker varm I2. f"-

An air supply pipe I4 communicates with 25 port I5 and air inlet valve I6. 'I'he valve I6 is actuated against 'the tension of spring I1 by rocker arm I2.- The valve I3, which is actuated by rocker arm II, permits the exhaust gases to pass out through port I3 into exhaust manifold 30 20. The piston 'I which is provided with the usual rings and piston pin, is of the trunk type rhas integrally formed on a part of its headV 2I a hollow boss 22adapted to extend into space 28 provided therefor in the cylinder head l. 35 This hollow boss, which is cfa general cylindrical form, is provided with an under-cut and somewhat liattened part 2l which provides a passage for the gases at one period of the cycle. 'I'he lower part or throat leading to the space 23 is 40 of circular section andof suitable size to provide working clearance for the upper partn of boss22. 0n one sldeof space 23 somewhat above the circular throat, 'a cutout portion 2l is provided. This cut out portion 2l is located 45 -oppooite to and in operating relation with the cut out section 2l of the boss 22. The wall of this cutout portion 231s curved to form a smooth passage for the gases entering the space 23. An injector 231s arranged with its nozzle extend- 50 Ing slightly through the curved wall of the cut out portion 2i.' f l In the operation of 'the engine it will be noted that when the piston rises'in the cylinderv com? pressing the gases. contained therein,-the upper 55 restricting the flow of the gases into this chamber and causing pressure to build up faster above head 2| than above the boss 22 in space 23. As the piston continues to rise and the pressure difference has increased to an appreciable amount the curved edge 21 of the piston boss 22 passes the curved' edge 28 in the wall of chamber 23, and from the space over the piston head 2 I, the gases, now heated to a high temperature by adiabatic compression, are suddenly released into chamber 23. These gases sweep along the w'all of the cut out space 25 and over the nozzle of injector 26 just at the time of injection, the fuel being supplied to the injector through tube 29 by fuel pump 30. As the fuel is thus injected into a rapidly moving stream ofhot gases it is thoroughly atomized and burned completely without the usual requirement of excess air.

It is to be noted that the fuel discharged from the injector 26 does not impingedirectly against any wall of the combustion chamber if it should pass entirely through the stream of gases, but is directed across a space of considerable magnitude, and the particles of fuel can come in contact with the walls of the chamber 23 only after they have been picked up and at least partly burned by the air contained in the gas stream.

By modications in the form of the cut out portion 24 of the boss 22 as. well as by changes in the contour of the wall of chamber 23 a wide `variety of changes can be made in the combustion characteristics of the engine. For variations in the speed and load conditions thetiming of the injection is modined, This is accomplished by thelmanpulation of control lever 3| on the fuel pump 30.

Numerous modifications may be made in the embodiments of my invention such as changing the angle and position of the injector to vary the relation of the fuel stream to the air or gas stream; the provision of two or more steps in the piston boss instead of only one as shown;

the direct connection of the fuel pump to thel rocker arm or cam shaft to eliminate the use of a separate exterior pump as shown on the present drawing, and numerous other modiiications which come within the scope of the fol- 2,234,844 l part of boss 22 enters the throat of chamber 23 combustion chamber during a part of the stroke ofthe piston to provide a substantial difference in pressure of gases in the two chambers. a valve controlling a flow of the gases, said valve being substantially coaxial with the aforesaid projection, means for establishing a passage between the combustion chambers before the completion of the aforesaid stroke to equalize the pressures in the two chambers by a sudden flow of a stream or the gases through the passage, and an injector disposed to inject fuel into said stream sub- 'stantially at the time of maximum velocity of gases through the passage, the fuel being directed across the space between the projection of the piston and theaforesaid valve.

2. In an engine of the type described, a cylin-f der, a piston operating in said cylinder, a large combustion chamber and a small combustion chamber, the piston having a projection adapted to enter the small combustion chamber to substantially isolate said chamber from the large combustion chamber during a part of the stroke of the piston to provide a greater pressure in the large combustion chamber than` in the small combustion chamber, means to establish a passage between the two chambers before the completion oi' the aforesaid stroke to equalize the pressures in the two chambers by a sudden flow of a stream oi' gases thru the passage into the small combustion chamber, said passage being provided by an undercut portion of said projection cooperating with a recess in the small chamber, and an injector disposed to inject fuel into the stream flowing in the recess substantially, at the beginning of flow thru the passage.

3. In an engine'of the type described, a cyl- Inder, a piston operating in said cylinder, a large combustion chamber and av small combustion chamber, the piston having a projection adapted to enter the small combustion chamber to substantially isolate said chamber from therlarge combustion chamber during a part'of the stroke of the piston to provide a greater pressure in the large combustion chamber than in the small combustion chamber. means to establish a passage between the two chambers before the completion of Athe aforesaid stroke to equalize the pressures in the two chambers by a sudden ilow of a stream of gases thru the passage into the small combustion chamber, said passage being provided by an undercut portion of said projection` cooperating with a recess in the small chamber, and an'injector extending thru a wall of the 'recess to inject fuel into the stream flowing therein.

COURTNEY N. MITCHELL. 

